1. Field of the Invention
The present invention relates to feed supplements and more particularly pertains to a new postpartum ketosis preventative feed supplement and method for alleviating a negative energy balance in ruminant animals.
2. Background History
During periods of negative energy balance, the postparturient dairy cow, periparturient ewes, and other ruminant animals suffer from carbohydrate insufficiency which is due to excessive fat mobilization from body stores and the development of fatty liver and ketosis.
The modern dairy cow is a product of genetic selection that produces milk beyond our ability to feed her. Virtually every cow loses body weight after calving, the result of body reserves mobilized to meet the energy needs of lactation. The reduction in body fat has an adverse effect on milk production. Although introduction of fat into the feed of ruminant animals lessens the conversion of existing body fat to fight the energy deficit, the proportion of fat in feed is limited due to adverse effects on the microorganisms of the rumen. An unavoidable reality contributing to this energy deficit is that anything eaten by an herbivore is first passed to the rumen where bacteria ferment nearly every gram of high energy carbohydrate. Consequently, it is universally recognized that no appreciable soluble sugars are presented postruminally to the abomasum or small intestine after exposure to the bacterial fermentation in the rumen. Therefore, direct comparison to monogastric carbohydrate metabolism does not provide immediate answers.
3. Description of the Prior Art
Current methods of preventing this condition and improving the carbohydrate status of these ruminant animals focus on increasing dietary carbohydrate in the form of starches and glucose precursors. The theory behind these methodologies is that the increase in dietary glucose precursors will increase blood glucose and insulin concentrations thereby suppressing mobilization of body fat and the formation of ketone bodies by the liver. Various examples may be found in U.S. Pat. Nos. 5,182,126; 6,126,986; 5,789,001; 5,219,596; 3,925,560; 5,874,102; 5,660,852; and 6,440,447.
Evidence exists, however, that bovine adipose tissue is not very responsive to insulin during the early postparturient period. Increases in blood insulin only minimally suppress fatty acid mobilization and serve to further decrease blood glucose concentrations by increasing glucose uptake by peripheral tissues. Further and most importantly, insulin concentrations are decreased in blood of animals suffering ketosis, limiting the uptake of glucose by tissues. Therefore, delivery of a carbohydrate source that is not dependent upon insulin for uptake by tissues will improve carbohydrate status during this period of hypoinsulinemia. The ideal compound would not be directly stimulatory to insulin. Such a carbohydrate could then be supplied to the tissue without further decreasing glucose concentrations in blood as is the case with insulin stimulating substrate, thus, alleviating carbohydrate insufficiency suffered by these ruminant animals.
U.S. Pat. No. 5,182,126 issued to Vinci et al. discusses the importance of blood glucose and the relative ineffectiveness of introducing glucose directly into feed. Vinci et al. as discussed generally above, focuses on gluconeogenesis by specifically teaching the use of glucogenous substances such as propionate in ruminally inert material to carry the glucose precursor past the rumen intact.
Studies have also been performed in monogastric carbohydrate metabolism to determine the effects of carbohydrates and proteins on blood glucose, glucagon, and insulin levels. Studies demonstrated that high carbohydrate diets typically increased insulin levels in greater proportion than glucagon while high protein diets promoted glucagon production and suppressed insulin production.
The need remains for a feed for ruminants and method that is readily absorbed by the animal, reduces stress on the liver, has little or no adverse effect on glucagon production, and does not stimulate insulin production. Thus, objectives of the present invention are to provide a feedstuff and method that provides sparing of glucose utilization, the prevention of ketosis, higher milk production, and quicker weight gain postpartum.